Long Term Evolution (LTE) is a standard for high-speed wireless communications for mobile devices and data terminals developed by the Third Generation Partnership Project (3GPP). Wideband LTE is an enhanced version of regular LTE that is made possible by combining multiple bands of spectrum. LTE-M is a version of LTE developed for the low power wide area (LPWA) technology standard.
LTE-M networks co-exist with 4G mobile networks and benefit from the security and privacy features provided by the network infrastructures of such mobile networks, such as support for user identity confidentiality, entity authentication, confidentiality, data integrity, and mobile equipment identification. LTE-M supports Internet of Things (IoT) applications through lower device complexity and provides extended coverage, while allowing the reuse of the already installed LTE network infrastructure. IoT applications are typically delay tolerant. In comparison, Wideband LTE is designed to carry different types of data traffic, including delay sensitive traffic such as voice data traffic (e.g., Voice over LTE or VoLTE).
The spectrum of Wideband LTE is divided into physical resource blocks (PRBs). A PRB is an allocation of subcarriers or frequency divisions for a predetermined amount of time. Each PRB is further divided along the time domain into time-divisions or subframes. Six PRBs of Wideband LTE are allocated to LTE-M, but an LTE base station may indicate to an LTE-M user device which subframes are not available for LTE-M communications. During subframes that are indicated as being not available to LTE-M traffic, LTE-M transmission and reception are skipped. The subframes marked as unavailable for LTE-M traffic may then be used for other purposes, such as conducting Wideband LTE communications.